1. Field of the Invention
This invention relates to motor home air-conditioning systems and methods. More particularly, it concerns devices and methods for improving the operation of on-board generators during use of air-conditioning in motor homes and the full utilization of multiple air-conditioning units.
2. Description of the Prior Art
The following disclosure of the invention discusses it with specific reference to motor homes. However, the invention is applicable to any comparable unit designed to provide mobile, personnel living quarters that are generally self-contained as to cooking, sleeping, toilet, power, etc., e.g., RVs, campers, trailers, boats or the like. Hence, the use of the term "motor home" throughout the specification and claims is intended to encompass all such type mobile living units.
In the conventional use of motor homes, whether on the road or without an external power source while stationary, the use of air-conditioning (A/C) requires operation of an on-board generator. This requires the push of a button to start the generator, then turn-on of the A/C and adjustment of the associated thermostat for the desired temperature. In such prior operations, the generator runs continually even though the A/C compressor is intermittently shut down by the thermostat. Not only is the continued running of the generator wasteful of fuel, but it is troublesome, particularly during sleeping hours, to the motor home occupants.
Many motor homes are equipped with more than one A/C unit, e.g., a plurality of roof units. In the conventional motor homes with multiple A/C units, when parked and plugged into external ac power, only one of the A/C units is operable. In many humid and/or hot environments, a single A/C unit is not sufficient to satisfactorily cool the motor home. In very recent motor homes, a switch has been provided that when actuated, allows more then one A/C unit to operate on the external power.
In view of the deficiencies with A/C operation in prior motor homes as indicated above, there exists a need for improvements in devices used to control operation of their A/C units in spite of numerous developments that have already been made in motor home A/C and refrigeration systems, including those disclosed in the following prior art U.S. patents:
______________________________________ 3,841,108 Pierrat 1974 3,885,398 Dawkins 1975 3,984,224 Dawkins 1976 4,051,691 Dawkins 1977. ______________________________________
The need to control refrigeration units in A/C systems or the like so as to coordinate with generator motors or other system motors in order to prevent system component damage is, of course, not unique with motor homes. Thus, the general problem exists relative to other vehicles, e.g., refrigerated trucks (see U.S. Pat. No. 2,962,873) and railway cars (see U.S. Pat. No. 4,006,603).
In an even broader sense, there exists many situations where timing the starting and stopping of internal combustion engines, whether used to power electrical generators or for other reason, upon repeated occurrences of temperature changes or other conditions, is required in order to protect the engine or other some other system unit against damage. Examples of this and of prior arrangements to solve the problem are found in the following prior art U.S. patents:
______________________________________ 2,337,164 Numero, etal. 1943 2,804,551 McFarland 1957 3,691,393 Papchristou 1972 4,463,305 Wineland, etal. 1984. ______________________________________
OBJECTS
A principal object of the invention is the provision of new and improved control devices and methods for air-conditioning systems of motor homes.
Further objects include the provision of:
1. Means to improve the operation of the on-board generator during use of air-conditioning in motor homes so the generator runs only when the thermostat demands the A/C unit(s) to run.
2. New control devices for use in attaining such improved operation.
3. Such control devices that also enable motor homes to use simultaneously a plurality of A/C units while hooked into an outside (dockside) power supply.
4. Such control devices that are adaptable for all motor homes from those with only one A/C unit to those with two, three, etc.
5. Such control devices that provide standby protection for the motor home should there be a power failure or interruption when it is parked and plugged into an external 120 VAC power source to prevent the inside of the MH from overheating through sun exposure.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.